ABSTRACTSolids obtained from laboratory solubility experiments in two different groundwaters from the Yucca Mountain region, Nevada, are described. The solubility study provided limiting solubility concentrations for neptunium(V), plutonium(IV), and americium(III) in groundwaters from Wells J-13 and UE-25p#l. The solubility-controlling solids are compared to relevant radionuclide compounds that are reported in the literature. The preparations and some characteristics of published solids that possibly may form in actinide-groundwater systems are described. The solids formed in the experiments are sodium neptunium(V) carbonates, polymeric Pu(IV) that contained small amounts of carbonate, and hexagonal or orthorhombic americium(III) hydroxycarbonates.
Measured solubilities and speciations of neptunium, plutonium, and americium in a typical groundwater (J-13) from the Yucca Mountain region; Milestone report 3010-WBS 1.2.3.4.1.3.1